Sage Therapeutics Announces Fourth Quarter and Full Year 2023 Financial Results and Highlights Pipeline and Business Progress ZURZUVAE (zuranolone), the first-and-only oral treatment indicated for adults with postpartum

Sage Therapeutics Announces Fourth Quarter and Full Year 2023 Financial Results and Highlights Pipeline

and Business Progress

ZURZUVAE (zuranolone), the first-and-only oral treatment indicated for adults with postpartum depression (PPD), became commercially available mid-December; Sage

achieved $0.8 million in collaboration revenue as of December 31, 2023, 50% of the net revenues Biogen reports for ZURZUVAE

Encouraging early launch results for ZURZUVAE with approximately 120 prescriptions in December

Catalyst rich 2024 with multiple topline data read-outs expected across dalzanemdor (SAGE-718) and SAGE-324 with potential for significant long-term value creation

Strong financial foundation with

year-end 2023 cash, cash equivalents and marketable securities of $753 million

Feb. 14, 2024 Sage Therapeutics, Inc. (Nasdaq: SAGE), a biopharmaceutical company leading the way to create a world with better brain health, today reported business highlights and financial results for the fourth quarter and full

year ended December 31, 2023.

2023 was a pivotal year for Sage, with key accomplishments achieved across our pipeline, culminating with the

recent encouraging launch of ZURZUVAE, the first-and-only once daily oral treatment for adults with postpartum depression. We are incredibly pleased with the early

progress on the launch. I am proud of our team s relentless work toward our goal of ZURZUVAE becoming the first line therapy for women with PPD and believe strongly in the potential for ZURZUVAE to make an impact in treating this devastating

disease, said Barry Greene, Chief Executive Officer at Sage Therapeutics. Beyond our ongoing commercialization efforts for ZURZUVAE, we look forward to delivering on multiple anticipated catalysts in 2024, including topline data from our

studies evaluating dalzanemdor and SAGE-324. We believe our work has the potential to make a difference in the lives of patients with brain health disorders, and we look forward to providing updates on our

progress over the coming quarters.

U.S. Food and Drug Administration (FDA) Approval of ZURZUVAE (zuranolone) for the treatment of adults with PPD: In December 2023, Sage and its

collaborator, Biogen, announced the commercial availability of ZURZUVAE indicated for the treatment of adults with PPD following its approval by the FDA in August 2023. Efforts to establish ZURZUVAE as the first line therapy and standard of care for

women with PPD are underway.

Continued advancement across innovative brain health pipeline with potential for significant long-term value creation: Sage continued to progress

enrollment across multiple Phase 2 studies in its clinical-stage pipeline which includes dalzanemdor (SAGE-718) and SAGE-324.

Fourth Quarter 2023 Portfolio Updates

advancing a portfolio of clinical-stage programs featuring internally discovered novel chemical entities with the potential to become differentiated products designed to improve brain health by targeting the GABAA and NMDA receptor systems.

Dysfunction in these systems is thought to be at the core of numerous neurological and neuropsychiatric disorders.

Postpartum Depression Commercial

ZURZUVAE was approved by the FDA in August 2023 as the

first-and-only oral treatment specifically indicated for adults with PPD. ZURZUVAE was made commercially available in December 2023. ZURZUVAE is being developed and

commercialized in collaboration with Biogen Inc. Sage also commercializes ZULRESSO (brexanolone) CIV injection in the treatment of PPD.

Sage and its collaborator, Biogen, are

focused on the goal of establishing ZURZUVAE as the first line therapy and standard of care for women with PPD. ZURZUVAE was made commercially available in December 2023. The companies are utilizing a specialty pharmacy distribution model by which

ZURZUVAE is shipped directly to women with PPD who are prescribed the treatment.

Initial launch data reflects demand from an estimated 10 days when

patients could access health care professional (HCP) offices. As of December 31, 2023, the following results had been achieved:

Sage and Biogen field sales teams are engaging in promotional dialogues with HCPs who actively identify and treat women with PPD. In December, prescriptions

were primarily written by OBGYNs and psychiatrists, who prescribed in approximately equal numbers. There were also a small number of prescriptions from PCPs.

The companies are advancing discussions with national, regional and government payors to advocate for broad and equitable access to ZURZUVAE for women with

PPD with minimal restrictions and expect formulary discussions to continue over the course of 2024. In the early launch, the vast majority of prescriptions were covered by payers.

At commercial availability, Sage and Biogen launched a patient support program, ZURZUVAE For You, which provides educational resources, help with

understanding insurance coverage, and assistance navigating the prescription fulfillment process. The program also includes financial assistance, such as a copay assistance program and product at no cost, for eligible patients. In December, the

commercially insured patients using the ZURZUVAE savings card paid no copay.

The Company expects the following milestones for ZURZUVAE in 2024:

Dalzanemdor (SAGE-718), the Company s

first-in-class NMDA receptor positive allosteric modulator (PAM), is in development as a potential oral therapy for cognitive impairment associated with

neurodegenerative disorders. Dalzanemdor has received Fast Track Designation and Orphan Drug Designation (ODD) from the FDA, and Orphan Drug Designation from the European Medicines Agency (EMA) for the potential treatment of Huntington s

Disease. Dalzanemdor has also been awarded an Innovation Passport Designation for cognitive impairment associated with HD and entry into the Innovative Licensing and Access Pathway (ILAP) by the U.K. Medicines and Healthcare products Regulatory

Agency (MHRA). SAGE-324, the Company s next-generation PAM of GABAA receptors, is in development as a potential oral therapy for movement disorders, such as essential tremor (ET). SAGE-324 is being developed in collaboration with Biogen Inc.

Sage is advancing a robust clinical program for dalzanemdor with multiple ongoing Phase 2

studies, including the DIMENSION and SURVEYOR Studies in people with cognitive impairment associated with Huntington s Disease (HD), the lead indication for dalzanemdor, the PRECEDENT Study in people with mild cognitive impairment

(MCI) associated with Parkinson s Disease (PD) and the LIGHTWAVE Study in people with MCI and mild dementia due to Alzheimer s Disease (AD).

In January 2024, the ILAP Steering Group awarded an Innovative Passport Designation to dalzanemdor for cognitive impairment associated with HD. Innovation

Passport Designation supports enhanced coordination of development activities, including access to a range of development tools and other potential benefits. Eligibility for the designation is based on a set of criteria including the potential to

treat a life-threatening or serious condition for which there is significant unmet need. ILAP does not necessarily lead to a faster development pathway or regulatory review process and does not increase the likelihood of regulatory approval.

Ongoing studies in the Dalzanemdor clinical program include:

The Company expects the following milestones for dalzanemdor in 2024:

Sage and its collaborator, Biogen, have completed enrollment in the Phase 2b KINETIC 2 placebo-controlled study of

SAGE-324 in ET, which follows positive results from the completed KINETIC Study of SAGE-324 in ET. KINETIC 2 is a Phase 2b dose-ranging study with the primary goal of

defining the dose for SAGE-324 with an efficacy and tolerability profile that maintains plasma concentrations needed for sustained tremor symptom control in treating ET. Topline data from the KINETIC 2 Study

are expected in mid-2024.

Sage is also enrolling patients in a Phase 2 long-term open-label safety study, to

evaluate the long-term safety and tolerability of SAGE-324 in ET. The primary endpoint is incidence of treatment-emergent adverse events.

The Company expects the following milestones for SAGE-324 in 2024:

FINANCIAL RESULTS FOR THE FOURTH QUARTER AND FULL YEAR 2023

Conference Call Information

Sage will host a conference call and webcast today, Wednesday, February 14, at 8:00 a.m. ET to review its fourth quarter and full year 2023 financial

results and discuss recent corporate updates. The live webcast can be accessed on the investor page of Sage s website at investor.sagerx.com. A replay of the webcast will be available on Sage s website following the completion of

the event and will be archived for up to 30 days.

About Sage Therapeutics

Sage Therapeutics (Nasdaq: SAGE) is a biopharmaceutical company committed to our mission of pioneering solutions to deliver life-changing brain health

medicines, so every person can thrive. Sage developed the only two FDA-approved treatments indicated for postpartum depression and is advancing a robust pipeline to target unmet needs in brain health. Sage was

founded in 2010 and is headquartered in Cambridge, Mass. Find out more at www.sagerx.com or engage with us on Facebook, LinkedIn, Instagram, and X.

Forward-Looking Statements

Various statements in

this release concern Sage s future expectations, plans and prospects, including without limitation our statements regarding: our plans, expectations and goals for commercialization of ZURZUVAE as a treatment for women with PPD, including our

goals for ZURZUVAE to become the first line treatment and standard of care in this indication; our belief in the potential for ZURZUVAE and our belief that ZURZUVAE will be successful in helping women with PPD; anticipated timelines for completion

of enrollment in clinical trials and reporting of results with respect to certain of our other programs; our belief in the potential profile and benefit of our product candidates; potential indications for our product candidates; the potential for

success of our programs, and the opportunity to help patients in various indications; our belief as to the key catalysts for our business and potential value creation; and the mission and goals for our business. These statements constitute

forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These forward-looking statements are neither promises nor guarantees of future performance, and are subject to a variety of risks and

uncertainties, many of which are beyond our control, which could cause actual results to differ materially from those contemplated in these forward-looking statements, including the risks that: our launch and commercialization efforts in the U.S.

with respect to ZURZUVAE for the treatment of women with PPD may not be successful, and we may be unable to generate revenues from sales of ZURZUVAE at the levels or on the timing we expect or at levels or on the timing necessary to support our

goals; early positive signs from launch or from our engagements with healthcare professionals, patients and payors related to ZURZUVAE may not be a signal of the potential for future success; the number of women with PPD, the unmet need for

additional treatment options, and the potential market for ZURZUVAE in women with PPD, may be significantly smaller than we expect; ZURZUVAE may not achieve the clinical benefit, clinical use or level of market acceptance from healthcare

professionals, patients or payors in the treatment of PPD we expect or we may encounter reimbursement-related or other market-related issues or issues with our distribution network that impact the success of our commercialization efforts, including

our ability to achieve access goals; ZURZUVAE may never become the first line treatment and standard of care for women with PPD; we may encounter delays in initiation,

conduct, completion of enrollment or completion and reporting of data with respect to any of our ongoing clinical trials, including as a result of slower than expected site initiation, slower

than expected enrollment, the need or decision to expand the trials or other changes, that may impact our ability to meet our expected timelines and may increase our costs; success in earlier clinical trials of any of our product candidates may not

be repeated or observed in ongoing or future studies, and ongoing and future clinical trials may not meet their primary or key secondary endpoints which may substantially impair development; unexpected concerns may arise from additional data,

analysis or results from any of our completed studies; decisions or actions of the FDA or the timing of meetings with the FDA may affect the timing, design, size, progress and cost of clinical trials or the timing of data read-outs or our ability to

proceed with further development or may impair the potential for successful development or the timing or success of filing for and gaining regulatory approval; we may encounter adverse events at any stage that negatively impact further development

and the potential for approval of our product candidates or the potential for successful commercialization of any our products or that require additional nonclinical and clinical work which may not yield positive results; the need to align with our

collaborators may hamper or delay our development and commercialization efforts for the products or product candidates that are part of the collaboration or increase our costs; the anticipated benefits of our ongoing collaborations, including the

receipt of payments or the successful development or commercialization of products and generation of revenue, may never be achieved at the levels or timing we expect or at all; our business may be adversely affected and our costs may increase if any

of our key collaborators fails to perform its obligations or terminates our collaboration; the internal and external costs required for our ongoing and planned activities, and the resulting impact on expense and use of cash, may be higher than

expected which may cause us to change or curtail some of our plans or both; we may not be successful in our efforts to gain regulatory approval of products beyond ZURZUVAE and ZULRESSO; we may not achieve revenues from our products that may be

successfully developed in the future, at levels we expect; additional funding may not be available on acceptable terms when we need it which could hamper our development and commercialization activities; any of the foregoing events could impair the

value creation opportunities for our business; and we may encounter technical and other unexpected hurdles in the development and manufacture of our product candidates or the commercialization of any current or future marketed product which may

delay our timing or change our plans, increase our costs or otherwise negatively impact our business; as well as those risks more fully discussed in the section entitled Risk Factors in our most recent annual or quarterly report filed

with the Securities and Exchange Commission, as well as discussions of potential risks, uncertainties, and other important factors in our subsequent filings with the Securities and Exchange Commission. In addition, any forward-looking statements

represent our views only as of today and should not be relied upon as representing our views as of any subsequent date. We explicitly disclaim any obligation to update any forward-looking statements.

Sage Therapeutics, Inc. and Subsidiaries

Condensed Consolidated Balance Sheets